LT1521 - 300mA Low Dropout Regulators with Micropower Quiescent Current and Shutdown

Features

  • Dropout Voltage: 0.5V
  • Output Current: 300mA
  • Quiescent Current: 12µA
  • No Protection Diodes Needed
  • Adjustable Output from 3.8V to 20V
  • Fixed Output Voltages: 3V, 3.3V, 5V
  • Controlled Quiescent Current in Dropout
  • Shutdown IQ = 6µA
  • Reverse Battery Protection
  • No Reverse Current
  • Thermal Limiting
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT1521 Typical Application
LT1521 Typical Application

Description

The LT1521/LT1521-3/LT1521-3.3/LT1521-5 are low dropout regulators with micropower quiescent current and shutdown. These devices are capable of supplying 300mA of output current with a dropout voltage of 0.5V.Designed for use in battery-powered systems, the low quiescent current, 12uA operating and 6uA in shutdown, makes them an ideal choice. The quiescent current is well controlled; it does not rise in dropout as it does with many other low dropout PNP regulators.

Other features of the LT1521/LT1521-3/LT1521-3.3/LT1521-5 include the ability to operate with very small output capacitors. They are stable with only 1.5uF on the output while most older devices require between 10uF and 100uF for stability. Small ceramic capacitors can be used,enhancing manufacturability. Also, the input may be connected to voltages lower than the output voltage, including negative voltages, without reverse current flow from output to input. This makes the LT1521 series ideal for backup power situations where the output is held high and the input is low or reversed. Under these conditions only 5uA will flow from the output pin to ground.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LT1521CMS8-3.3#PBF MS-8 MS8 C 05-08-1660 Yes
LT1521CMS8-3.3#TRPBF MS-8 MS8 C 05-08-1660 Yes
LT1521CMS8-3#PBF MS-8 MS8 C 05-08-1660 Yes
LT1521CMS8-3#TRPBF MS-8 MS8 C 05-08-1660 Yes
LT1521CMS8-5#PBF MS-8 MS8 C 05-08-1660 Yes
LT1521CMS8#PBF MS-8 MS8 C 05-08-1660 Yes
LT1521CS8-3.3#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8-3.3#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8-3#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8-3#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8-5#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8-5#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8#PBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CS8#TRPBF SO-8 S8 C 05-08-1610 (S8) Yes
LT1521CST-3.3#PBF SOT-223 ST C 05-08-1630 Yes
LT1521CST-3.3#TRPBF SOT-223 ST C 05-08-1630 Yes
LT1521CST-3#PBF SOT-223 ST C 05-08-1630 Yes
LT1521CST-3#TRPBF SOT-223 ST C 05-08-1630 Yes
LT1521CST-5#PBF SOT-223 ST C 05-08-1630 Yes
LT1521CST-5#TRPBF SOT-223 ST C 05-08-1630 Yes
LT1521IS8-3.3#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8-3.3#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8-3#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8-3#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8-5#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8-5#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8#PBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IS8#TRPBF SO-8 S8 I 05-08-1610 (S8) Yes
LT1521IST-3.3#PBF SOT-223 ST I 05-08-1630 Yes
LT1521IST-3.3#TRPBF SOT-223 ST I 05-08-1630 Yes
LT1521IST-3#PBF SOT-223 ST I 05-08-1630 Yes
LT1521IST-3#TRPBF SOT-223 ST I 05-08-1630 Yes
LT1521IST-5#PBF SOT-223 ST I 05-08-1630 Yes
LT1521IST-5#TRPBF SOT-223 ST I 05-08-1630 Yes


LT1521 Package Drawing
LT1521 Package Drawing
LT1521 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT1521CMS8-3.3#PBF MS-8 C $2.65 $2.20 Yes
LT1521CMS8-3.3#TRPBF MS-8 C $2.26 Yes
LT1521CMS8-3#PBF MS-8 C $2.65 $2.20 Yes
LT1521CMS8-3#TRPBF MS-8 C $2.26 Yes
LT1521CMS8-5#PBF MS-8 C $2.65 $2.20 Yes
LT1521CMS8#PBF MS-8 C $2.65 $2.20 Yes
LT1521CS8-3.3#PBF SO-8 C $2.75 $2.20 Yes
LT1521CS8-3.3#TRPBF SO-8 C $2.26 Yes
LT1521CS8-3#PBF SO-8 C $2.75 $2.20 Yes
LT1521CS8-3#TRPBF SO-8 C $2.26 Yes
LT1521CS8-5#PBF SO-8 C $2.75 $2.20 Yes
LT1521CS8-5#TRPBF SO-8 C $2.26 Yes
LT1521CS8#PBF SO-8 C $2.75 $2.20 Yes
LT1521CS8#TRPBF SO-8 C $2.26 Yes
LT1521CST-3.3#PBF SOT-223 C $2.36 $1.90 Yes
LT1521CST-3.3#TRPBF SOT-223 C $1.96 Yes
LT1521CST-3#PBF SOT-223 C $2.36 $1.90 Yes
LT1521CST-3#TRPBF SOT-223 C $1.96 Yes
LT1521CST-5#PBF SOT-223 C $2.36 $1.90 Yes
LT1521CST-5#TRPBF SOT-223 C $1.96 Yes
LT1521IS8-3.3#PBF SO-8 I $3.35 $2.65 Yes
LT1521IS8-3.3#TRPBF SO-8 I $2.71 Yes
LT1521IS8-3#PBF SO-8 I $3.35 $2.65 Yes
LT1521IS8-3#TRPBF SO-8 I $2.71 Yes
LT1521IS8-5#PBF SO-8 I $3.35 $2.65 Yes
LT1521IS8-5#TRPBF SO-8 I $2.71 Yes
LT1521IS8#PBF SO-8 I $3.35 $2.65 Yes
LT1521IS8#TRPBF SO-8 I $2.71 Yes
LT1521IST-3.3#PBF SOT-223 I $3.15 $2.55 Yes
LT1521IST-3.3#TRPBF SOT-223 I $2.61 Yes
LT1521IST-3#PBF SOT-223 I $3.15 $2.55 Yes
LT1521IST-3#TRPBF SOT-223 I $2.61 Yes
LT1521IST-5#PBF SOT-223 I $3.15 $2.55 Yes
LT1521IST-5#TRPBF SOT-223 I $2.61 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Designed for Automotive and Transportation Appications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT1521IST-3.3#PBF SOT-223 I $3.15 $2.55 Yes
LT1521IST-3.3#TRPBF SOT-223 I $2.61 Yes
LT1521IST-3#PBF SOT-223 I $3.15 $2.55 Yes
LT1521IST-3#TRPBF SOT-223 I $2.61 Yes
LT1521IST-5#PBF SOT-223 I $3.15 $2.55 Yes
LT1521IST-5#TRPBF SOT-223 I $2.61 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Applications

  • Low Current Regulator
  • Regulator for Battery-Powered Systems
  • Post Regulator for Switching Supplies

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Design Tools

LTspiceIV

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Models for the following parts are available in LTspice IV:
LT1521
LT1521-3
LT1521-3.3
LT1521-5

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